Remove TabContents from TabStripModelObserver::TabReplacedAt.

chrome/browser/ui/gtk/tabs/tab_strip_gtk.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/tabs/tab_strip_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 1118 matching lines @@
     // We'll receive another notification of the change asynchronously.
     return;
   }
   tab->UpdateData(contents,
                   model_->IsAppTab(index),
                   change_type == LOADING_ONLY);
   tab->UpdateFromModel();
 }
 
 void TabStripGtk::TabReplacedAt(TabStripModel* tab_strip_model,
-                                TabContents* old_contents,
-                                TabContents* new_contents,
+                                WebContents* old_contents,
+                                WebContents* new_contents,
                                 int index) {
-  TabChangedAt(new_contents->web_contents(), index, ALL);
+  TabChangedAt(new_contents, index, ALL);
 }
 
 void TabStripGtk::TabMiniStateChanged(WebContents* contents, int index) {
   // Don't do anything if we've already picked up the change from TabMoved.
   if (GetTabAt(index)->mini() == model_->IsMiniTab(index))
     return;
 
   GetTabAt(index)->set_mini(model_->IsMiniTab(index));
   // Don't animate if the window isn't visible yet. The window won't be visible
   // when dragging a mini-tab to a new window.
@@ skipping 1114 matching lines @@
 
 void TabStripGtk::SetNewTabButtonBackground() {
   SkColor color = theme_service_->GetColor(
       ThemeService::COLOR_BUTTON_BACKGROUND);
   SkBitmap background = theme_service_->GetImageNamed(
       IDR_THEME_WINDOW_CONTROL_BACKGROUND).AsBitmap();
   SkBitmap mask = theme_service_->GetImageNamed(
       IDR_NEWTAB_BUTTON_MASK).AsBitmap();
   newtab_button_->SetBackground(color, background, mask);
 }